POS1037 THE GUT MICROBIOME IN PATIENTS WITH ESTABLISHED RHEUMATOID ARTHRITIS: FACTORS ASSOCIATED WITH COMPOSITION, AND ITS VALUE FOR PREDICTING TREATMENT RESPONSES
Authors: J. H. Koh, E. H. Lee, K. H. Cha, C. H. Pan, D. Kim, W. U. Kim
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> The gut microbiota has been proposed to be an important environmental factor in the development of rheumatoid arthritis (RA). However, changes in the gut microbiome of RA patients who were already treated with disease-modifying anti-rheumatic drugs (DMARDs) have not been studied well. <h3>Objectives</h3> We aimed to investigate the gut microbiota of patients with established rheumatoid arthritis (RA) who have been managed with DMARDs for a long time. We focused on factors that might affect composition of the gut microbiota. Furthermore, we investigated whether gut microbiota composition predicts future clinical responses to conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) in patients with an insufficient response to initial therapy. <h3>Methods</h3> We recruited 94 patients with RA and 30 healthy participants. Fecal samples were collected, and the gut microbiome was analyzed by 16S rRNA amplificon sequencing. Calypso online software was used to compare microbial composition between groups. For RA patients with moderate-to-high disease activity, treatment was changed after stool collection, and responses were observed 6 months later. <h3>Results</h3> The composition of the gut microbiota in patients with established RA was different from that of healthy participants. Young RA patients (&lt; 45 years) had reduced richness, evenness, and distinct gut microbial compositions when compared with older RA patients and healthy individuals. Disease activity and rheumatoid factor levels were not associated with microbiome composition. Overall, biological DMARDs and csDMARDs, except sulfasalazine and TNF inhibitors, respectively, were not associated with the gut microbial composition in patients with established RA. However, the combination of <i>Subdoligranulum</i> and <i>Fusicatenibacter</i> genera was associated with a future good response to second-line csDMARDs in patients who showed an insufficient response to first-line csDMARDs. <h3>Conclusion</h3> Gut microbial composition in patients with established RA is different from that in healthy individuals. Thus, the gut microbiome has the potential to predict responses of some RA patients to csDMARDs. <h3>References</h3> [1] Bergot AS, Giri R, Thomas R: <b>The microbiome and rheumatoid arthritis</b>. <i>Best Pract Res Clin Rheumatol</i> 2019, <b>33</b>(6):101497. [2] Kishikawa T, Maeda Y, Nii T, Motooka D, Matsumoto Y, Matsushita M, Matsuoka H, Yoshimura M, Kawada S, Teshigawara S <i>et al</i>: <b>Metagenome-wide association study of gut microbiome revealed novel aetiology of rheumatoid arthritis in the Japanese population</b>. <i>Ann Rheum Dis</i> 2020, <b>79</b>(1):103-111. [3] Maeda Y, Kurakawa T, Umemoto E, Motooka D, Ito Y, Gotoh K, Hirota K, Matsushita M, Furuta Y, Narazaki M et al: <b>Dysbiosis Contributes to Arthritis Development via Activation of Autoreactive T Cells in the Intestine</b>. Arthritis Rheumatol 2016, 68(11):2646-2661. <h3>Acknowledgements</h3> This work was supported by National Research Foundation of Korea grants funded by the Ministry of Science, ICT and Future Planning (Grant 2015R1A3A2032927 to W.U. Kim), a National Research Foundation of Korea grant funded by the Ministry of Education (Grant 2017R1D1A1B04033009 to D. Kim WU), and the Liu Inkyung Memorial Endowment Fund through Seoul National University (D. Kim DH). <h3>Disclosure of Interests</h3> None Declared.